Relaying in a device-to-device communication system

ABSTRACT

The present aspects relate to device-to-device (D2D) relaying in a wireless communication system. In an aspect, a remote user equipment (UE) may transmit, on at least one sidelink channel, a scheduling request to a relay UE connected with a network entity. The remote UE may further receive, on one or more sidelink channels, a scheduling indication including a resource grant from the relay UE in response to transmitting the scheduling request. In a further aspect, a relay UE may receive, on at least one sidelink channel, a scheduling request from a remote UE. The relay UE may further determine, a resource grant for the remote UE in response to receiving the scheduling request. The relay UE may further transmit, on one or more sidelink channels, a scheduling indication including the resource grant to the remote UE.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit of U.S. Provisional Application Ser.No. 62/502,363, entitled “RELAYING IN A DEVICE-TO-DEVICE COMMUNICATIONSYSTEM” and filed on May 5, 2017, which is expressly incorporated byreference herein in its entirety.

BACKGROUND

The present disclosure relates generally to communication systems, andmore particularly, to device-to-device (D2D) relay communication.

Wireless communication systems are widely deployed to provide varioustelecommunication services such as telephony, video, data, messaging,and broadcasts. Typical wireless communication systems may employmultiple-access technologies capable of supporting communication withmultiple users by sharing available system resources. Examples of suchmultiple-access technologies include code division multiple access(CDMA) systems, time division multiple access (TDMA) systems, frequencydivision multiple access (FDMA) systems, orthogonal frequency divisionmultiple access (OFDMA) systems, single-carrier frequency divisionmultiple access (SC-FDMA) systems, and time division synchronous codedivision multiple access (TD-SCDMA) systems.

These multiple access technologies have been adopted in varioustelecommunication standards to provide a common protocol that enablesdifferent wireless devices to communicate on a municipal, national,regional, and even global level. An example telecommunication standardis Long Term Evolution (LTE). LTE is a set of enhancements to theUniversal Mobile Telecommunications System (UMTS) mobile standardpromulgated by Third Generation Partnership Project (3GPP). LTE isdesigned to support mobile broadband access through improved spectralefficiency, lowered costs, and improved services using OFDMA on thedownlink, SC-FDMA on the uplink, and multiple-input multiple-output(MIMO) antenna technology. However, as the demand for mobile broadbandaccess continues to increase, there exists a need for furtherimprovements in LTE technology. These improvements may also beapplicable to other multi-access technologies and the telecommunicationstandards that employ these technologies.

For example, current implementation of D2D communication may inhibit adesired level of efficient operation with respect to power and resourceutilization. Thus, improvements in wireless communication operations maybe desired.

SUMMARY

The following presents a simplified summary of one or more aspects inorder to provide a basic understanding of such aspects. This summary isnot an extensive overview of all contemplated aspects, and is intendedto neither identify key or critical elements of all aspects nordelineate the scope of any or all aspects. Its sole purpose is topresent some concepts of one or more aspects in a simplified form as aprelude to the more detailed description that is presented later.

In an aspect, the present disclosure includes a method for wirelesscommunications at a relay user equipment (UE). The method may includereceiving, on at least one sidelink channel, a scheduling request from aremote UE. The method may further include determining a resource grantfor the remote UE in response to receiving the scheduling request. Themethod may further include transmitting, on one or more sidelinkchannels, a scheduling indication including the resource grant to theremote UE.

In another aspect, the present disclosure includes a relay UE forwireless communication comprising a memory and a processor incommunication with the memory. The processor may be configured toreceive, on at least one sidelink channel, a scheduling request from aremote UE. The processor may further be configured to determine, by therelay UE, a resource grant for the remote UE in response to receivingthe scheduling request. The processor may further be configured totransmit, on one or more sidelink channels, a scheduling indicationincluding the resource grant to the remote UE.

In an additional aspect, the present disclosure includes a relay UE forwireless communication including means for receiving, on at least onesidelink channel, a scheduling request from a remote UE. The relay UEmay further include means for determining, by the relay UE, a resourcegrant for the remote UE in response to receiving the scheduling request.The relay UE may further include means for transmitting, on one or moresidelink channels, a scheduling indication including the resource grantto the remote UE.

In yet another aspect, the present disclosure include acomputer-readable medium storing computer executable code for wirelesscommunications at a relay UE. The computer-readable medium may includecode for receiving, on at least one sidelink channel, a schedulingrequest from a remote UE. The computer-readable medium may furtherinclude code for determining, by the relay UE, a resource grant for theremote UE in response to receiving the scheduling request. Thecomputer-readable medium may further include code for transmitting, onone or more sidelink channels, a scheduling indication including theresource grant to the remote UE.

In an aspect, the present disclosure includes a method for wirelesscommunications at a remote UE. The method may include transmitting, onat least one sidelink channel, a scheduling request to a relay UEconnected with a network entity. The remote UE may further receive, onone or more sidelink channels, a scheduling indication including aresource grant from the relay UE in response to transmitting thescheduling request.

In another aspect, the present disclosure includes a remote UE forwireless communication comprising a memory and a processor incommunication with the memory. The processor may be configured totransmit, on at least one sidelink channel, a scheduling request to arelay UE connected with a network entity. The processor may further beconfigured to receive, on one or more sidelink channels, a schedulingindication including a resource grant from the relay UE in response totransmitting the scheduling request.

In an additional aspect, the present disclosure includes a remote UE forwireless communication including means for transmitting, on at least onesidelink channel, a scheduling request to a relay UE connected with anetwork entity. The remote UE may further include means for receiving,on one or more sidelink channels, a scheduling indication including aresource grant from the relay UE in response to transmitting thescheduling request.

In yet another aspect, the present disclosure include acomputer-readable medium storing computer executable code for wirelesscommunications at a remote UE. The computer-readable medium may includecode for transmitting, on at least one sidelink channel, a schedulingrequest to a relay UE connected with a network entity. Thecomputer-readable medium may further include code for receiving, on oneor more sidelink channels, a scheduling indication including a resourcegrant from the relay UE in response to transmitting the schedulingrequest.

To the accomplishment of the foregoing and related ends, the one or moreaspects comprise the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail certain illustrative featuresof the one or more aspects. These features are indicative, however, ofbut a few of the various ways in which the principles of various aspectsmay be employed, and this description is intended to include all suchaspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of a wireless communicationssystem and an access network.

FIGS. 2A, 2B, 2C, and 2D are diagrams illustrating LTE examples of a DLframe structure, DL channels within the DL frame structure, an UL framestructure, and UL channels within the UL frame structure, respectively.

FIG. 3 is a diagram illustrating an example of an evolved Node B (eNB)and user equipment (UE) in an access network.

FIG. 4 is a diagram of a device-to-device communications systemincluding a relay UE having a relay component and a remote UE having acommunication component.

FIG. 5 is a flowchart of a method of relaying a radio network temporaryidentifier (RNTI) at a relay UE.

FIG. 6 is a flowchart of a method of RNTI reception at a remote UE.

FIG. 7 is a flowchart of a method of resource allocation at a remote UE.

FIG. 8 is a flowchart of a method of resource allocation at a relay UE.

FIG. 9 is a flowchart of a method of wireless communication at a remoteUE.

FIG. 10 is a flowchart of a method of scheduling resources at a relayUE.

FIG. 11 is a conceptual data flow diagram illustrating the data flowbetween different means/components in an example apparatus such as arelay UE having a relay component.

FIG. 12 is a diagram illustrating an example of a hardwareimplementation for an apparatus employing a processing system.

FIG. 13 is a conceptual data flow diagram illustrating the data flowbetween different means/components in an example apparatus such as aremote UE having a communication component.

FIG. 14 is a diagram illustrating an example of a hardwareimplementation for an apparatus employing a processing system.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings is intended as a description of various configurations and isnot intended to represent the only configurations in which the conceptsdescribed herein may be practiced. The detailed description includesspecific details for the purpose of providing a thorough understandingof various concepts. However, it will be apparent to those skilled inthe art that these concepts may be practiced without these specificdetails. In some instances, well known structures and components areshown in block diagram form in order to avoid obscuring such concepts.

Several aspects of telecommunication systems will now be presented withreference to various apparatus and methods. These apparatus and methodswill be described in the following detailed description and illustratedin the accompanying drawings by various blocks, components, circuits,processes, algorithms, etc. (collectively referred to as “elements”).These elements may be implemented using electronic hardware, computersoftware, or any combination thereof. Whether such elements areimplemented as hardware or software depends upon the particularapplication and design constraints imposed on the overall system.

By way of example, an element, or any portion of an element, or anycombination of elements may be implemented as a “processing system” thatincludes one or more processors. Examples of processors includemicroprocessors, microcontrollers, graphics processing units (GPUs),central processing units (CPUs), application processors, digital signalprocessors (DSPs), reduced instruction set computing (RISC) processors,systems on a chip (SoC), baseband processors, field programmable gatearrays (FPGAs), programmable logic devices (PLDs), state machines, gatedlogic, discrete hardware circuits, and other suitable hardwareconfigured to perform the various functionality described throughoutthis disclosure. One or more processors in the processing system mayexecute software. Software shall be construed broadly to meaninstructions, instruction sets, code, code segments, program code,programs, subprograms, software components, applications, softwareapplications, software packages, routines, subroutines, objects,executables, threads of execution, procedures, functions, etc., whetherreferred to as software, firmware, middleware, microcode, hardwaredescription language, or otherwise.

Accordingly, in one or more example embodiments, the functions describedmay be implemented in hardware, software, or any combination thereof. Ifimplemented in software, the functions may be stored on or encoded asone or more instructions or code on a computer-readable medium.Computer-readable media includes computer storage media. Storage mediamay be any available media that can be accessed by a computer. By way ofexample, and not limitation, such computer-readable media can comprise arandom-access memory (RAM), a read-only memory (ROM), an electricallyerasable programmable ROM (EEPROM), optical disk storage, magnetic diskstorage, other magnetic storage devices, combinations of theaforementioned types of computer-readable media, or any other mediumthat can be used to store computer executable code in the form ofinstructions or data structures that can be accessed by a computer.

FIG. 1 is a diagram illustrating an example of a wireless communicationssystem and an access network 100. The wireless communications system(also referred to as a wireless wide area network (WWAN)) includes basestations 102, UEs 104, and an Evolved Packet Core (EPC) 160. Forexample, UE 104 a and UE 104 b may be communicating via adevice-to-device (D2D). D2D communication may be used to provide directcommunication between devices such as UEs. D2D communication enables onedevice to communicate with another device and transmit data to the otherdevice over allocated resources. In an aspect, the UE 104 a may includerelay component 410 configured to relay information from the basestation 102 to the UE 104 b and/or from the UE 104 b to the base station102. Further, in an aspect, the UE 104 b may include communicationcomponent 420 configured to facilitate sidelink communication with theUE 104 a. In some aspects, one or both of the UE 104 a and/or 104 b maybe in a connected state with base station 102. The base stations 102 mayinclude macro cells (high power cellular base station) and/or smallcells (low power cellular base station). The macro cells include eNBs.The small cells include femtocells, picocells, and microcells.

The base stations 102 (collectively referred to as Evolved UniversalMobile Telecommunications System (UMTS) Terrestrial Radio Access Network(E-UTRAN)) interface with the EPC 160 through backhaul links 132 (e.g.,S1 interface). In addition to other functions, the base stations 102 mayperform one or more of the following functions: transfer of user data,radio channel ciphering and deciphering, integrity protection, headercompression, mobility control functions (e.g., handover, dualconnectivity), inter-cell interference coordination, connection setupand release, load balancing, distribution for non-access stratum (NAS)messages, NAS node selection, synchronization, radio access network(RAN) sharing, multimedia broadcast multicast service (MBMS), subscriberand equipment trace, RAN information management (RIM), paging,positioning, and delivery of warning messages. The base stations 102 maycommunicate directly or indirectly (e.g., through the EPC 160) with eachother over backhaul links 134 (e.g., X2 interface). The backhaul links134 may be wired or wireless.

The base stations 102 may wirelessly communicate with the UEs 104. Eachof the base stations 102 may provide communication coverage for arespective geographic coverage area 110. There may be overlappinggeographic coverage areas 110. For example, the small cell 102′ may havea coverage area 110′ that overlaps the coverage area 110 of one or moremacro base stations 102. A network that includes both small cell andmacro cells may be known as a heterogeneous network. A heterogeneousnetwork may also include Home Evolved Node Bs (eNBs) (HeNBs), which mayprovide service to a restricted group known as a closed subscriber group(CSG). The communication links 120 between the base stations 102 and theUEs 104 may include uplink (UL) (also referred to as reverse link)transmissions from a UE 104 to a base station 102 and/or downlink (DL)(also referred to as forward link) transmissions from a base station 102to a UE 104. The communication links 120 may use MIMO antennatechnology, including spatial multiplexing, beamforming, and/or transmitdiversity. The communication links may be through one or more carriers.The base stations 102/UEs 104 may use spectrum up to Y MHz (e.g., 5, 10,15, 20 MHz) bandwidth per carrier allocated in a carrier aggregation ofup to a total of Yx MHz (x component carriers) used for transmission ineach direction. The carriers may or may not be adjacent to each other.Allocation of carriers may be asymmetric with respect to DL and UL(e.g., more or less carriers may be allocated for DL than for UL). Thecomponent carriers may include a primary component carrier and one ormore secondary component carriers. A primary component carrier may bereferred to as a primary cell (PCell) and a secondary component carriermay be referred to as a secondary cell (SCell).

The wireless communications system may further include a Wi-Fi accesspoint (AP) 150 in communication with Wi-Fi stations (STAs) 152 viacommunication links 154 in a 5 GHz unlicensed frequency spectrum. Whencommunicating in an unlicensed frequency spectrum, the STAs 152/AP 150may perform a clear channel assessment (CCA) prior to communicating inorder to determine whether the channel is available.

The small cell 102′ may operate in a licensed and/or an unlicensedfrequency spectrum. When operating in an unlicensed frequency spectrum,the small cell 102′ may employ LTE and use the same 5 GHz unlicensedfrequency spectrum as used by the Wi-Fi AP 150. The small cell 102′,employing LTE in an unlicensed frequency spectrum, may boost coverage toand/or increase capacity of the access network. LTE in an unlicensedspectrum may be referred to as LTE-unlicensed (LTE-U), licensed assistedaccess (LAA), or MuLTEfire.

The millimeter wave (mmW) base station 180 may operate in mmWfrequencies and/or near mmW frequencies in communication with the UE182. Extremely high frequency (EHF) is part of the RF in theelectromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and awavelength between 1 millimeter and 10 millimeters. Radio waves in theband may be referred to as a millimeter wave. Near mmW may extend downto a frequency of 3 GHz with a wavelength of 100 millimeters. The superhigh frequency (SHF) band extends between 3 GHz and 30 GHz, alsoreferred to as centimeter wave. Communications using the mmW/near mmWradio frequency band has extremely high path loss and a short range. ThemmW base station 180 may utilize beamforming 184 with the UE 182 tocompensate for the extremely high path loss and short range.

The EPC 160 may include a Mobility Management Entity (MME) 162, otherMMEs 164, a Serving Gateway 166, a Multimedia Broadcast MulticastService (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC)170, and a Packet Data Network (PDN) Gateway 172. The MME 162 may be incommunication with a Home Subscriber Server (HSS) 174. The MME 162 isthe control node that processes the signaling between the UEs 104 andthe EPC 160. Generally, the MME 162 provides bearer and connectionmanagement. All user Internet protocol (IP) packets are transferredthrough the Serving Gateway 166, which itself is connected to the PDNGateway 172. The PDN Gateway 172 provides UE IP address allocation aswell as other functions. The PDN Gateway 172 and the BM-SC 170 areconnected to the IP Services 176. The IP Services 176 may include theInternet, an intranet, an IP Multimedia Subsystem (IMS), a PS StreamingService (PSS), and/or other IP services. The BM-SC 170 may providefunctions for MBMS user service provisioning and delivery. The BM-SC 170may serve as an entry point for content provider MBMS transmission, maybe used to authorize and initiate MBMS Bearer Services within a publicland mobile network (PLMN), and may be used to schedule MBMStransmissions. The MBMS Gateway 168 may be used to distribute MBMStraffic to the base stations 102 belonging to a Multicast BroadcastSingle Frequency Network (MBSFN) area broadcasting a particular service,and may be responsible for session management (start/stop) and forcollecting eMBMS related charging information.

The base station may also be referred to as a Node B, evolved Node B(eNB), an access point, a base transceiver station, a radio basestation, a radio transceiver, a transceiver function, a basic serviceset (BSS), an extended service set (ESS), or some other suitableterminology. The base station 102 provides an access point to the EPC160 for a UE 104. Examples of UEs 104 include a cellular phone, a smartphone, a session initiation protocol (SIP) phone, a laptop, a personaldigital assistant (PDA), a satellite radio, a global positioning system,a multimedia device, a video device, a digital audio player (e.g., MP3player), a camera, a game console, a tablet, a smart device, a wearabledevice, or any other similar functioning device. The UE 104 may also bereferred to as a station, a mobile station, a subscriber station, amobile unit, a subscriber unit, a wireless unit, a remote unit, a mobiledevice, a wireless device, a wireless communications device, a remotedevice, a mobile subscriber station, an access terminal, a mobileterminal, a wireless terminal, a remote terminal, a handset, a useragent, a mobile client, a client, or some other suitable terminology.

Referring again to FIG. 1, in certain aspects, the UE 104 may beconfigured to perform congestion control based on an energy-basedchannel busy ratio and/or a decode-based channel busy ratio and tocontrol packet transmission based on packet priorities and a channelbusy ratio (198).

FIG. 2A is a diagram 200 illustrating an example of a DL frame structurein LTE. FIG. 2B is a diagram 230 illustrating an example of channelswithin the DL frame structure in LTE. FIG. 2C is a diagram 250illustrating an example of an UL frame structure in LTE. FIG. 2D is adiagram 280 illustrating an example of channels within the UL framestructure in LTE. Other wireless communication technologies may have adifferent frame structure and/or different channels. In LTE, a frame (10ms) may be divided into 10 equally sized subframes. Each subframe mayinclude two consecutive time slots. A resource grid may be used torepresent the two time slots, each time slot including one or more timeconcurrent resource blocks (RBs) (also referred to as physical RBs(PRBs)). The resource grid is divided into multiple resource elements(REs). In LTE, for a normal cyclic prefix, an RB contains 12 consecutivesubcarriers in the frequency domain and 7 consecutive symbols (for DL,OFDM symbols; for UL, SC-FDMA symbols) in the time domain, for a totalof 84 REs. For an extended cyclic prefix, an RB contains 12 consecutivesubcarriers in the frequency domain and 6 consecutive symbols in thetime domain, for a total of 72 REs. The number of bits carried by eachRE depends on the modulation scheme.

As illustrated in FIG. 2A, some of the REs carry DL reference (pilot)signals (DL-RS) for channel estimation at the UE. The DL-RS may includecell-specific reference signals (CRS) (also sometimes called common RS),UE-specific reference signals (UE-RS), and channel state informationreference signals (CSI-RS). FIG. 2A illustrates CRS for antenna ports 0,1, 2, and 3 (indicated as R₀, R₁, R₂, and R₃, respectively), UE-RS forantenna port 5 (indicated as R₅), and CSI-RS for antenna port 15(indicated as R). FIG. 2B illustrates an example of various channelswithin a DL subframe of a frame. The physical control format indicatorchannel (PCFICH) is within symbol 0 of slot 0, and carries a controlformat indicator (CFI) that indicates whether the physical downlinkcontrol channel (PDCCH) occupies 1, 2, or 3 symbols (FIG. 2B illustratesa PDCCH that occupies 3 symbols). The PDCCH carries downlink controlinformation (DCI) within one or more control channel elements (CCEs),each CCE including nine RE groups (REGs), each REG including fourconsecutive REs in an OFDM symbol. A UE may be configured with aUE-specific enhanced PDCCH (ePDCCH) that also carries DCI. The ePDCCHmay have 2, 4, or 8 RB pairs (FIG. 2B shows two RB pairs, each subsetincluding one RB pair). The physical hybrid automatic repeat request(ARQ) (HARQ) indicator channel (PHICH) is also within symbol 0 of slot 0and carries the HARQ indicator (HI) that indicates HARQ acknowledgement(ACK)/negative ACK (NACK) feedback based on the physical uplink sharedchannel (PUSCH). The primary synchronization channel (PSCH) is withinsymbol 6 of slot 0 within subframes 0 and 5 of a frame, and carries aprimary synchronization signal (PSS) that is used by a UE to determinesubframe timing and a physical layer identity. The secondarysynchronization channel (SSCH) is within symbol 5 of slot 0 withinsubframes 0 and 5 of a frame, and carries a secondary synchronizationsignal (SSS) that is used by a UE to determine a physical layer cellidentity group number. Based on the physical layer identity and thephysical layer cell identity group number, the UE can determine aphysical cell identifier (PCI). Based on the PCI, the UE can determinethe locations of the aforementioned DL-RS. The physical broadcastchannel (PBCH) is within symbols 0, 1, 2, 3 of slot 1 of subframe 0 of aframe, and carries a master information block (MIB). The MIB provides anumber of RBs in the DL system bandwidth, a PHICH configuration, and asystem frame number (SFN). The physical downlink shared channel (PDSCH)carries user data, broadcast system information not transmitted throughthe PBCH such as system information blocks (SIBs), and paging messages.

As illustrated in FIG. 2C, some of the REs carry demodulation referencesignals (DM-RS) for channel estimation at the eNB. The UE mayadditionally transmit sounding reference signals (SRS) in the lastsymbol of a subframe. The SRS may have a comb structure, and a UE maytransmit SRS on one of the combs. The SRS may be used by an eNB forchannel quality estimation to enable frequency-dependent scheduling onthe UL. FIG. 2D illustrates an example of various channels within an ULsubframe of a frame. A physical random access channel (PRACH) may bewithin one or more subframes within a frame based on the PRACHconfiguration. The PRACH may include six consecutive RB pairs within asubframe. The PRACH allows the UE to perform initial system access andachieve UL synchronization. A physical uplink control channel (PUCCH)may be located on edges of the UL system bandwidth. The PUCCH carriesuplink control information (UCI), such as scheduling requests, a channelquality indicator (CQI), a precoding matrix indicator (PMI), a rankindicator (RI), and HARQ ACK/NACK feedback. The PUSCH carries data, andmay additionally be used to carry a buffer status report (BSR), a powerheadroom report (PHR), and/or UCI.

FIG. 3 is a block diagram of an eNB 310 in communication with a UE 350in an access network. The UE 350 may include at least one of a relaycomponent 410 configured to relay information from the eNB 310 to aremote UE and/or from the remote UE to the eNB 310, or a communicationcomponent 420 configured to facilitate sidelink communication withanother UE. In the DL, IP packets from the EPC 160 may be provided to acontroller/processor 375. The controller/processor 375 implements layer3 and layer 2 functionality. Layer 3 includes a radio resource control(RRC) layer, and layer 2 includes a packet data convergence protocol(PDCP) layer, a radio link control (RLC) layer, and a medium accesscontrol (MAC) layer. The controller/processor 375 provides RRC layerfunctionality associated with broadcasting of system information (e.g.,MIB, SIBs), RRC connection control (e.g., RRC connection paging, RRCconnection establishment, RRC connection modification, and RRCconnection release), inter radio access technology (RAT) mobility, andmeasurement configuration for UE measurement reporting; PDCP layerfunctionality associated with header compression/decompression, security(ciphering, deciphering, integrity protection, integrity verification),and handover support functions; RLC layer functionality associated withthe transfer of upper layer packet data units (PDUs), error correctionthrough ARQ, concatenation, segmentation, and reassembly of RLC servicedata units (SDUs), re-segmentation of RLC data PDUs, and reordering ofRLC data PDUs; and MAC layer functionality associated with mappingbetween logical channels and transport channels, multiplexing of MACSDUs onto transport blocks (TBs), demultiplexing of MAC SDUs from TBs,scheduling information reporting, error correction through HARQ,priority handling, and logical channel prioritization.

The transmit (TX) processor 316 and the receive (RX) processor 370implement layer 1 functionality associated with various signalprocessing functions. Layer 1, which includes a physical (PHY) layer,may include error detection on the transport channels, forward errorcorrection (FEC) coding/decoding of the transport channels,interleaving, rate matching, mapping onto physical channels,modulation/demodulation of physical channels, and MIMO antennaprocessing. The TX processor 316 handles mapping to signalconstellations based on various modulation schemes (e.g., binaryphase-shift keying (BPSK), quadrature phase-shift keying (QPSK),M-phase-shift keying (M-PSK), M-quadrature amplitude modulation(M-QAM)). The coded and modulated symbols may then be split intoparallel streams. Each stream may then be mapped to an OFDM subcarrier,multiplexed with a reference signal (e.g., pilot) in the time and/orfrequency domain, and then combined together using an Inverse FastFourier Transform (IFFT) to produce a physical channel carrying a timedomain OFDM symbol stream. The OFDM stream is spatially precoded toproduce multiple spatial streams. Channel estimates from a channelestimator 374 may be used to determine the coding and modulation scheme,as well as for spatial processing. The channel estimate may be derivedfrom a reference signal and/or channel condition feedback transmitted bythe UE 350. Each spatial stream may then be provided to a differentantenna 320 via a separate transmitter 318TX. Each transmitter 318TX maymodulate an RF carrier with a respective spatial stream fortransmission.

At the UE 350, each receiver 354RX receives a signal through itsrespective antenna 352. Each receiver 354RX recovers informationmodulated onto an RF carrier and provides the information to the receive(RX) processor 356. The TX processor 368 and the RX processor 356implement layer 1 functionality associated with various signalprocessing functions. The RX processor 356 may perform spatialprocessing on the information to recover any spatial streams destinedfor the UE 350. If multiple spatial streams are destined for the UE 350,they may be combined by the RX processor 356 into a single OFDM symbolstream. The RX processor 356 then converts the OFDM symbol stream fromthe time-domain to the frequency domain using a Fast Fourier Transform(FFT). The frequency domain signal comprises a separate OFDM symbolstream for each subcarrier of the OFDM signal. The symbols on eachsubcarrier, and the reference signal, are recovered and demodulated bydetermining the most likely signal constellation points transmitted bythe eNB 310. These soft decisions may be based on channel estimatescomputed by the channel estimator 358. The soft decisions are thendecoded and deinterleaved to recover the data and control signals thatwere originally transmitted by the eNB 310 on the physical channel. Thedata and control signals are then provided to the controller/processor359, which implements layer 3 and layer 2 functionality.

The controller/processor 359 can be associated with a memory 360 thatstores program codes and data. The memory 360 may be referred to as acomputer-readable medium. In the UL, the controller/processor 359provides demultiplexing between transport and logical channels, packetreassembly, deciphering, header decompression, and control signalprocessing to recover IP packets from the EPC 160. Thecontroller/processor 359 is also responsible for error detection usingan ACK and/or NACK protocol to support HARQ operations.

Similar to the functionality described in connection with the DLtransmission by the eNB 310, the controller/processor 359 provides RRClayer functionality associated with system information (e.g., MIB, SIBs)acquisition, RRC connections, and measurement reporting; PDCP layerfunctionality associated with header compression/decompression, andsecurity (ciphering, deciphering, integrity protection, integrityverification); RLC layer functionality associated with the transfer ofupper layer PDUs, error correction through ARQ, concatenation,segmentation, and reassembly of RLC SDUs, re-segmentation of RLC dataPDUs, and reordering of RLC data PDUs; and MAC layer functionalityassociated with mapping between logical channels and transport channels,multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs,scheduling information reporting, error correction through HARQ,priority handling, and logical channel prioritization.

Channel estimates derived by a channel estimator 358 from a referencesignal or feedback transmitted by the eNB 310 may be used by the TXprocessor 368 to select the appropriate coding and modulation schemes,and to facilitate spatial processing. The spatial streams generated bythe TX processor 368 may be provided to different antenna 352 viaseparate transmitters 354TX. Each transmitter 354TX may modulate an RFcarrier with a respective spatial stream for transmission.

The UL transmission is processed at the eNB 310 in a manner similar tothat described in connection with the receiver function at the UE 350.Each receiver 318RX receives a signal through its respective antenna320. Each receiver 318RX recovers information modulated onto an RFcarrier and provides the information to a RX processor 370.

The controller/processor 375 can be associated with a memory 376 thatstores program codes and data. The memory 376 may be referred to as acomputer-readable medium. In the UL, the controller/processor 375provides demultiplexing between transport and logical channels, packetreassembly, deciphering, header decompression, control signal processingto recover IP packets from the UE 350. IP packets from thecontroller/processor 375 may be provided to the EPC 160. Thecontroller/processor 375 is also responsible for error detection usingan ACK and/or NACK protocol to support HARQ operations.

FIG. 4 is a diagram of a D2D communications system 460. The D2Dcommunications system 460 includes a plurality of UEs 464, 466, 468,470. The D2D communications system 460 may overlap with a cellularcommunications system, such as for example, a WWAN. Some of the UEs 464,466, 468, 470 may communicate together in D2D communication using theDL/UL WWAN spectrum, some may communicate with the base station 462(e.g., via communication links 432 and/or 434), and some may do both.For example, as shown in FIG. 4, the UEs 468, 470 are in D2Dcommunication and the UEs 464, 466 are in D2D communication. The UEs464, 466 are also communicating with the base station 462. The D2Dcommunication may be through one or more sidelink channels (e.g.,sidelink channel 430), such as, but not limited to, a physical sidelinkbroadcast channel (PSBCH), a physical sidelink discovery channel(PSDCH), a physical sidelink shared channel (PSSCH), and a physicalsidelink control channel (PSCCH).

The UE 464 may correspond to a relay UE and the UE 466 may correspond toa remote UE. The UE 464 may include the relay component 410, which maybe configured to relay information from the base station 462 to theremote UE 466 and/or from the UE 466 to the base station 462. Further,the remote UE 466 may include communication component 420, which may beconfigured to facilitate sidelink communication with the relay UE 464.

In an aspect related to the RNTI component 412 at the UE 464 and theRNTI reception component 422 at the remote UE 466, one or more radionetwork temporary identifier (RNTIs) for D2D based bi-directionalrelating may be implemented. In some aspects, an RNTI is a physicallayer identifier of the UE allocated by a base station (e.g., eNB).Specifically, a D2D relaying may provide efficiency in power andresource utilization. For instance, a remote UE such the remote UE 466(e.g., smartwatch) may have limited batteries and/or power supply. Whenthe remote UE 466 is communicating with the base station 462, the remoteUE 466 may transmit at higher power (e.g., as opposed to communicatingwith the relay UE 464 on a sidelink). As such, when communicating withthe relay UE such as the relay UE 464, the remote UE 466 may consumelower power for transmission and receptions. Hence, relaying assistswith conserving power at the remote UE 466. Also, from a resourceutilization point of view, the remote UE 466 may reuse at least some ofthe same resources between the relay UE 464 and the remote UE 466 by thebase station 462, thereby increasing system capacity.

D2D relaying may include uni-directional relaying and/or bi-directionalrelaying. Uni-directional relaying may be used to relay only uplinktraffic from the remote UE 466 to the base station 462 via the relay UE464, while downlink traffic to the remote UE 466 may be transmitteddirectly to the remote UE 466. However, with bi-directional relaying,both uplink traffic from and downlink traffic to the remote UE 466 maybe relayed by the relay UE 464 to/from the base station 462.

The remote UE 466 and the relay UE 464 may utilize a PC5 (D2Dcommunication) interface for communication. Rel-12 and Rel-13 D2Dcommunication may be based on a fixed number of retransmissions andtransmission power based on an open loop power control with respect tothe base station 462. However, such approach may not utilize feedbackfrom other UEs to adjust a number of retransmissions and transmissionpower.

The remote UE 466. which may correspond to a remote UE typically, mayonly have a single receiver (Rx) chain, and as such, may only be tunedto or otherwise listen to the base station 462 or the relay UE 464. Forexample, in one instance, the remote UE 466 may be tuned to the relay UE464, but the base station 462 may be controlling the resources allocatedto one or both of the relay UE 464 and/or remote UE 466 for sidelinkcommunication. Accordingly, it may be desirable to have the relay UE 464relay RNTI information to the UE 466 on at least one sidelink channel430.

For example, to allocate resources and during connection setup, the basestation 462 may provide one or more RNTIs to the relay UE 464 and mayalso indicate to the remote UE 466 to establish a sidelink (e.g., PC5)connection with relay UE 464. As such, the base station 462 may control,via RRC messaging, when the remote UE 466 is listening to the relay UE464 or when the remote UE 466 is listening to the UE 464 (e.g., whensidelink is disconnected, remote UE 466 will automatically connect toeNB for at least downlink communication). In some aspects, although theremote UE 466 is no longer listening to the base station 462, the remoteUE 466 and the base station 462 may maintain a logical connection evenwhen the remote UE 466 is connected to the relay UE 464.

The relay UE 464 may receive the one or more RNTIs, which may include anRNTI of the relay UE 464 and an RNTI of the remote UE 466. The UE 464may perform scheduling of resources for the remote UE 466 based on thebase stations 462 command. Specifically, for the RNTI of the UE relay464, the relay UE 464 may decode the physical downlink control channel(PDCCH) to determine whether there a downlink and/or uplink grant hasbeen allocated by the base station 462. Similarly, for the RNTI of theremote UE 466, the relay UE 464 may decode the PDCCH to determinewhether a grant of sidelink resources has been allocated for the remoteUE 466. Based on determining that a grant of sidelink resources has beenprovided for the remote UE 466, the relay UE 464 may forward the grantor associated RNTI to the remote UE 466 to facilitate bi-directionalcommunication on the sidelink.

In some aspects, the base station 462 may provide a single RNTI for eachremote UE 466 that is connected with relay UE 464, or may provide a bulkRNTI for all remote UEs 466 connected with the relay UE 464. Forexample, the relay UE 464 may monitor PDCCH for RNTI's of remote UEs466, in addition to the relay UE's 464 own RNTI. Specifically, a bulkRNTI may be received by the relay UE 464. In such instance, the downlinkcontrol information (DCI) may distinguish the remote UEs including theremote UE 466. Indexing may be performed using RRC connection setup ofremote UEs. The bulk RNTI message may include an index to the remoteUEs. In some aspects, the index may have been pre-negotiated between thebase station 462 and the relay UE 464 in an RRC message. Further, foreach remote UE identifier, there may be an index assigned to each remoteUE. Based on the index, the relay UE 464 may determine the remote UEidentifier for which the grant is allocated.

In the case where a single RNTI may be determined and forwarded to acorresponding remote UE 466, the relay UE 464 may obtain the single RNTIassociated with the remote UE 466 for determining the sidelink grantallocated by the base station 462 for the remote UE 466. The relay UE464 may perform such procedure for each distinct RNTI associated withdifferent remote UEs. As such, in either case, the relay UE 464 receivesan indication including one or more RNTIs of remote UEs 466, and basedon the indication, the relay UE 464 may decode PDCCH from the basestation 462 to obtain the grant, and passes the grant onto the remote UE466.

In some aspects, the relay UE 464 may be a high capability UE (e.g.,smartphone) in terms of battery and capacity (e.g., may support MIMO,carrier aggregation, etc.). Further, the remote UE 466 may be a lowcapability device (e.g., smartwatch) with respect to battery andcommunication capabilities.

In some aspects, the relay UE 464 and the remote UE 466 may beassociated with each other. For example, the relay UE 464 and the remoteUE 466 may be associated with a single or same subscriber or operatorsubscription. Further, during connection establishment, the base station462 may possess the association information (e.g., devices share samesubscription)

In an aspect related to the resource allocation component 414 at therelay UE 464 and the resource component 424 at the remote UE 466,eNB-assisted resource allocation for sidelink communication between theremote UE 466 and the relay UE 464 may be provided. For example, D2Dcommunication may include two modes of resource allocation for sidelinkcommunication: (i) UE autonomous, and (ii) eNB-based (e.g., base station462). In the case of UE autonomous resource allocation, the eNB may setaside resource pools to be used for sidelink communication and the UEmay autonomously (e.g., randomly and/or based on distributed sensingbased MAC) select the resources within the pool for transmissions. Inthe case of eNB-based resource allocation, the UE requests the eNB for aresource and the eNB grants the resources to the UE. For out-of-coveragesidelink operations, resource selection may always be UE autonomous.

For the case of a remote UE 466 (e.g., which may be a wearable device),the remote UE 466 may either not be in-coverage of the base station 462,or may be power limited and associated to a relay UE 464 to communicateto the base station 462. Thus, in addition to the above approaches(i.e., UE autonomous and eNB-based), the present aspects overcome suchshortcomings such that the base station 462 may assign the resources forthe remote UE 466 via the sidelink relay connection. An eNB-assistedresource allocation may provide better coexistence with regular uplinktransmissions and improved link performance using centralized resourceallocation.

Further, the remote UE 466 (e.g., wearable UE) may be bandwidth limited(e.g., capable of monitoring only six radio bearers within the channelbandwidth). Hence, if the base station 462 assigns a resource to therelay UE 464 for sidelink communication with the remote UE 466, theremote UE 466 may also need to be informed of the 6 PRB sub-pool tomonitor for that transmission.

Additionally, if the remote UE 466 receives the DCI with resourceallocation from the eNB such as base station 462 in subframe ‘n’, thenthe resource may be for the subframe ‘n+4’. However, it may be desirableto have the eNB allocate a resource for the remote UE 466, but suchinformation is relayed via a relay UE 464 via sidelink. So if conductedusing DCI by the eNB, the ‘n+4’ may be modified as the relay UE 464forwarding delay should be accounted.

In the case of a relayed link, the remote UE such as the remote UE 466may not have a timing advance available from the eNB (e.g., no directuplink link between remote and eNB). For eNB assigned/assisted resourceallocation, it may still be desired to assign an appropriate timingadvance for remote UE's transmission for better coexistence with otherUL transmissions.

In one example, the eNB such the base station 462 may allocate resources(e.g., sidelink resources) to both the remote UE 466 and relay UE 464.The relay UE may then forward the resources to remote UE in atransparent manner. For example, the relay UE 464 may receive DCI forrelaying UE resource (e.g., may be scrambled with relay UE 464'sC-RNTI). Further, the relay UE 464 may receive DCI for remote UEresource, but the resource may be for time ‘n+T’, where ‘n’ is asubframe and ‘T’ may be a time value. In some aspects, ‘T’ may be RRCconfigured. Additionally, the configuration may be sidelink poolspecific. In some aspects, T may be a fixed value such as eight (e.g.,implemented when there are HARQ retransmissions).

The DCI may be scrambled with a remote-RNTI being monitored by the relayUE 464 for the purpose of relaying to either the remote UE 466, or agroup of remote UEs associated with the relay UE 464. Further, the DCImay be transmitted as an enhanced physical downlink control channel(E-PDCCH) and may include ‘T’ as a parameter, i.e., T may be part ofDCI.

The relay UE 464 may relay the DCI to the remote UE 466. In oneinstance, the DCI may be sent as sidelink control information (SCI)without any associated data. In another instance, the DCI may be sent asa MAC control element and part of sidelink link shared channel (SL-SCH)data. Additionally, a time ‘X’ after which the allocation applies may bedetermined such that n′+X=n+T, where n′ is the subframe on which the DCIis relayed to the remote UE 466.

In another example, the eNB such as base station 462 may allocate bulkresources to the relay UE 464, and the relay UE 464 then sub-allocatesand forwards the resources to the remote UE 466 in a transparent manner.For example, the base station 462 may transmit an initial resourceallocation in accordance with a semi-persistent scheduling (SPS)configuration to the relay UE 464 for both the relay UE 464 and theremote UE 466 resources. The relay UE 464 may then sub-allocateresources from the SPS resources to the remote UE 466. In one instance,the relay UE 464 may allocate one resource at a time. In anotherinstance, as a sub-SPS process, the relay UE 464 may first be informedof the periodicity and then transmit according to n′+X using DCI or aMAC CE.

In a further example, the resource pools for the remote UE 466 may beconfigured using RRC by the base station 462 (e.g., the RRC messages maybe sent directly or indirectly via the relay UE 464). The resource poolmay hop in frequency using predetermined pattern.

Further, to address the timing variance, the remote UE 466 may apply atiming advance to sidelink transmissions. In one example, the relay UE464 may inform the remote UE 466 of the timing advance to apply. Thetiming advance may be derived in at least two manners. First, the relayUE 464 may inform the remote UE 466 of the timing advance of the relayUE 464. Such information may be sent as MAC CE or SCI. Second, the relayUE 464 may inform the remote UE 466 of the timing advance. For example,the timing advance may be the relay UE's own TA in addition to acorrection (e.g., correction may be within the autonomous correctionlimit. Further, the timing advance of the relay UE's 464 timing advancein addition to the correction (e.g., correction may be within somelimits configured by the eNB). Additionally, the correction may be basedon any sidelink transmission from the remote UE 466 and the relay UE464.

In another example, the remote UE 466 may derive the timing for sidelinktransmission based on a sidelink synchronization signal (SLSS)transmitted by the relay UE 464. For example, the SLSS may be sent withan uplink timing by the relay UE 464. Further, the remote UE 466 maythen follows the timing advance of the relay UE 464 with a correction asinformed by the relay UE 464 and/or autonomous corrections made in itsend. Additionally, the relay UE 464 can inform the remote UE 466 of thecorrections to apply over the received SLSS timing at the remote UE 466based on measurements over any sidelink transmission from the remote UE466 to the relay UE 464.

In an aspect related to the scheduling determination component 416 atthe relay UE 464 and the scheduling component 426 at the remote UE 466,scheduling requests (SRs) and buffer status reports (BSRs) on PC5sidelink interface between the remote UE 466 and the relay UE 464 may beprovided.

Some sidelink designs may not include any particular L2 MAC controlsignaling for peer UEs to facilitate scheduling. For the relay UE 464 toact as a L2 relay, the remote UE 466 may be visible to the base station462. The remote UE 466 may be logically connected to the base station462, but the base station 462 may not allocate physical resources forthe remote UE 466. Thus, there may not be a need to have SR or BSRbetween the remote UE 466 and the base station 462 for schedulingpurposes. However, as the remote UE 466 may still need to obtainresource allocated by the relay UE 464, signaling such as SR and BSRover the sidelink interface may be desirable. The present aspectsprovide an SR and BSR signaling scheme using at least two MAC CEs overthe sidelink within an L1 or L2 signaling exchange in sidelink fordirect resource allocation between the remote UE 466 and the relay UE464.

For a mode 1 UE, the remote UE 466 may rely on the eNB to allocate PC5sidelink resource dynamically. For a mode 2 UE, the remote UE 466 mayread SIB 21 or use pre-configured sidelink resource to transmit its dataover PC5 interface. However, for a UE that is neither in mode 1 nor inmode 2, the UE may be in a third mode where the eNB may not directly beinvolved in remote resource assignment over sidelink. From the remote UE466 perspective, the sidelink resources may be assigned by the relay UE464. In this case, scheduling requests may be transmitted on thesidelink between the remote UE 466 and relay UE 464.

For example, the D2D UEs may perform synchronous resource allocation forSR (or RTS). Unlike asynchronous on-demand RTS operation, the resourceto send SR may be short and periodic. The resource may be used tosupport code-division multiplexing (CDM) such that multiple remote UEsincluding remote UE 466 can transmit in the resource at the same time.The relay UE 464 may discern the transmitter(s) or distinct remote UEsby identifying different code(s) used in the CDM scheme. In this SR,1-bit of information may be transmitted by each remote UE as a requestfor relay-allocated resource to be used for sidelink operation.

The resources that are transmitted according to CDM for SR may bepre-allocated as periodic resources when the remote UE 466 is linked tothe relay UE 464. The actual configuration for those resources may bedetermined either by the relay UE 464 or the eNB 462. If the eNB 462,RRC dedicated signaling or SIB may be used. Further, some of the PC5data resources are statically configured as potential SR resources aspart of PSDCH. Additionally, the SR response (CTS) may be generated bythe relay UE 464 on-demand and may not use pre-assigned resources. Ifthe relay UE 464 includes an SR response in a MAC CE within the DATAportion, the relay UE 464 may indicate the SR response in SCI precedingthe DATA.

For the remote UE 466 linked to the relay 464, the BSR may be similar toan RTS of the relay UE. For example, the BSR may be transmitted as a MACCE over the sidelink, the remote UE 466 may generate BSR (e.g., forsidelink buffer) and include the BSR as part of the “DATA” transmittedto the relay UE 464. However, the relay UE 464 may extract this part ofDATA and discern the contents represented by the BSR message and adjustthe scheduling decisions accordingly. To provide the relay UE 464 anindication that there is a BSR MAC CE in the DATA portion of thetransmission, the SCI (L1 Signaling) transmitted preceding the data mayinclude a flag to indicate such.

The exemplary methods and apparatuses discussed infra are applicable toany of a variety of wireless D2D communications systems, such as forexample, a wireless device-to-device communication system based onFlashLinQ, WiMedia, Bluetooth, ZigBee, or Wi-Fi based on the IEEE 802.11standard. To simplify the discussion, the exemplary methods andapparatus are discussed within the context of LTE. However, one ofordinary skill in the art would understand that the exemplary methodsand apparatuses are applicable more generally to a variety of otherwireless device-to-device communication systems.

FIG. 5 is a flowchart 500 of a method of relaying an RNTI at a relay UE.The method may be performed by a UE (e.g., UE 464). At block 502, themethod may receive, on a downlink channel from a network entity, atleast one message including a RNTI of a remote UE associated with therelay UE. For example, as described herein, the relay UE 464 and/or theRNTI component 412 may execute the RNTI component 412 to receive, on adownlink channel (e.g., Uu interface) from a network entity (e.g., basestation 462), at least one message including a RNTI of a remote UE 466associated with the relay UE 464. At block 504, method may transmit, ona sidelink channel, a sidelink grant associated with the RNTI to theremote UE. For example, as described herein, the relay UE 464 and/or theRNTI component 412 may execute the RNTI component 412 to transmit, on asidelink channel 430, a sidelink grant associated with the RNTI to theremote UE 466.

In some aspects, the message may include an index including one or moreindex values each associated with one of the RNTI of the remote UE 466and one or more additional RNTIs of one or more distinct remote UEs. Forexample, the index may be a listing of a plurality of distinct indexvalues each associated with an RNTI of a different remote UE. Althoughnot shown, the method 500 may further determine an index valueassociated with the remote UE 466, identify/determine the RNTI of theremote UE 466 based on the index value, and determine the sidelink grantfor the remote UE 466 based on the RNTI of the remote UE 466. In someaspects, the sidelink grant may be transmitted to the remote UE 466 onthe sidelink channel 430 in accordance with a determination of the RNTIbased on the index value.

In some aspects, determining the sidelink grant for the remote UE 466may include decoding the downlink channel following reception of themessage including the RNTI of the remote UE 466 to obtain the sidelinkgrant for the remote UE 466 associated with the RNTI of the remote UE466. In some aspects, the downlink channel may corresponds to a PDCCH.In some aspects, the method may further establish the sidelink channel430 with the remote UE 466, the sidelink channel 430 corresponding to aPC5 interface. In some aspects, the remote UE 466 may share an operatorsubscription with the relay UE 464. In some aspects, the RNTI of theremote UE 466 may be associated with a grant of radio resources on thesidelink channel 430. In some aspects, the relay UE 464 may be a highcapability UE and the remote UE 466 may be a low capability UE.

FIG. 6 is a flowchart 600 of a method of RNTI reception at a remote UE.The method may be performed by a UE (e.g., UE 466). At block 602, themethod may receive, on a downlink channel from a network entity, anindication to establish a connection with a relay UE on a sidelinkchannel, the relay UE being in a connected state with the networkentity. For example, as described herein, the remote UE 466 and/or thecommunication component 420 may execute the RNTI reception component 422to receive, on a downlink channel from a network entity (e.g., basestation 462), an indication to establish a connection with a relay UE464 on a sidelink channel 430, the relay UE 464 being in a connectedstate with the network entity.

At block 604, the method may establish the connection with the relay UEon the sidelink channel. For example, as described herein, the remote UE466 and/or the communication component 420 may execute the RNTIreception component 422 to establish the connection with the relay UE466 on the sidelink channel 430. At block 606, the method may receive,on the sidelink channel 430, a sidelink grant associated with an RNTI ofthe remote UE from the relay UE. For example, as described herein, theremote UE 466 and/or the communication component 420 may execute theRNTI reception component 422 to receive, on the sidelink channel 430, asidelink grant associated with an RNTI of the remote UE 466 from therelay UE 464.

In some aspects, the sidelink channel 430 may correspond to a PC5interface. In some aspects, the remote UE 466 may share an operatorsubscription with the relay UE 464. In some aspects, the sidelink grantprovides radio resources for bi-directional communication on thesidelink channel 430. In some aspects, the relay UE 464 may be a highcapability UE and the remote UE 466 may be a low capability UE.

FIG. 7 is a flowchart 700 of a method of resource allocation at a relayUE. The method may be performed by a UE (e.g., UE 464). At block 702,the method may receive, on a downlink channel from a network entity, atleast one indication including resource allocation information for atleast one of the relay UE or a remote UE. For example, as describedherein, the relay UE 464 and/or the relay component 410 may execute theresource allocation component 414 to receive, on a downlink channel froma network entity (e.g., base station 462), at least one indicationincluding resource allocation information for at least one of the relayUE 464 or a remote UE 466. At block 704, the method may transmit, on asidelink channel to the remote UE, the resource allocation informationof remote UE. For example, as described herein, the relay UE 464 and/orthe relay component 410 may execute the resource allocation component414 to transmit, on a sidelink channel 430, the resource allocationinformation to the remote UE 466.

In some aspects, the resource allocation information may correspond toDCI including resource allocation for at least one of the relay UE 464or the remote UE 466 at a first time value representing a subframe slotplus a first time variable associated with the resource allocation. Insome aspects, the time variable may correspond at least one of a fixedvalue or a RRC configured value. In some aspects, the DCI may bescrambled with at least a C-RNTI of the relay UE 464 or an RNTI of theremote UE 466. In some aspects, the DCI is transmitted via an E-PDCCH.

In some aspects, transmitting the resource allocation information to theremote UE 466 may include transmitting the DCI as SCI without associateddata to the remote UE 466, and/or transmitting DCI as a MAC CE as partof the SL-SCH data. In some aspects, the DCI may be transmitted at asecond time value representing the subframe slot plus a second timevariable less than the first time variable. Although not shown, in someaspects, the method 700 may determine the second time variable such thatthe first time value plus the first time variable is the same as orequal to the second time value plus or in addition to the second timevariable.

In some aspects, the resource allocation information may include orcorrespond to a bulk allocation of resources for one or more remote UEsincluding the remote UE 466 and associated with a SPS configuration. Insome aspects, transmitting the resource allocation information to theremote UE may include allocating, for at least the remote UE 466, asingle resource from the resources at a distinct time.

In some aspects, the indication may further includes a periodicityindication associated with an SPS-RNTI, the periodicity indicationrepresenting a repetition period for the bulk allocation of resources.In some aspects, transmitting the resource allocation information to theremote UE may include transmitting the DCI as SCI without associateddata to the remote UE, or transmitting DCI as a MAC CE as part of theSL-SCH data.

In some aspects, although not shown, the method 700 may determine afirst timing advance information, and transmit the first timing advanceinformation to the remote UE 466. Further, in some aspects, determiningthe first timing advance information may include receiving, from anetwork entity, a second timing advance information for use intransmissions between the relay UE 464 and the network entity (e.g.,base station 462), and setting the first timing advance informationequal to the second timing advance information.

In some aspects, determining the first timing advance information mayinclude receiving, from a network entity (e.g., base station 462), asecond timing advance information for use in transmissions between therelay UE 464 and the network entity (e.g., base station 462),determining a timing offset based on a received timing of one or moresidelink channels (e.g., sidelink channel 430), and setting the firsttiming advance information as a function of the second timing advanceinformation and the timing offset. Further, although not shown, in someaspects, the method 700 may further determine whether the timing offsetis within at least one of a minimum limit or maximum limit, and adjustthe timing offset to at least one of the minimum limit or the maximumlimit.

In some aspects, at least one of the minimum limit or maximum limit maybe within a fixed autonomous timing correction limit allowed by thenetwork entity (e.g., base station 462). In some aspects, at least oneof the minimum limit or maximum limit is received as an RRCconfiguration from a network entity (e.g., base station 462). In someaspects, the method may further transmit one or more sidelinksynchronization signals to the remote UE 466 utilizing timing thatcorresponds to the first timing advance information.

FIG. 8 is a flowchart 800 of a method of resource allocation at a remoteUE. The method may be performed by a UE (e.g., UE 464). At block 802,the method may receive, on at least one sidelink channel, resourceallocation information from a relay UE, the resource allocationinformation indicating one or more resources allocated for sidelinkcommunication for the remote UE. For example, as described herein, theremote UE 466 and/or the communication component 420 may execute theresource component 424 to receive, on at least one sidelink channel 430,resource allocation information from a relay UE 464, the resourceallocation information indicating one or more resources allocated forsidelink communication for the remote UE 466.

At block 804, the method may optionally receive, on the at least onesidelink channel, timing information from the relay UE. For example, asdescribed herein, the remote UE 466 and/or the communication component420 may execute the resource component 424 to receive, on the at leastone sidelink channel 430, timing information from the relay UE 464. Atblock 708, the method may transmit, on one or more sidelink channels,data to the relay UE in accordance with at least one of the one or moreresources allocated for sidelink communication or the timinginformation. For example, as described herein, the remote UE 466 and/orthe communication component 420 may execute the resource component 424to transmit, on one or more sidelink channels (e.g., sidelink channel430), data to the relay UE 464 in accordance with at least one of theone or more resources allocated for sidelink communication or the timinginformation.

In some aspects, receiving the timing information may include receivingat least one of timing advance information of the relay UE 464 or timingadvance information of the remote UE 466. In some aspects, receiving thetiming information may include detecting a sidelink synchronizationsignal transmitted by the relay UE 464, and determining timing advanceinformation based on the sidelink synchronization signal. In someaspects, the resource allocation information corresponds to at least oneof one or more resources allocated by a network entity (e.g., basestation 462) or the relay UE 464.

In some aspects, a network entity (e.g., eNB such as base station 462)may designate a set of bulk resources to the relay UE 464 for all itsremote UEs including remote UE 466 which are linked to the relay UE 464.

FIG. 9 is a flowchart 900 of a method of wireless communication at aremote UE. The method may be performed by a UE (e.g., UE 466). At block902, the method may transmit, on at least one sidelink channel, ascheduling request to a relay UE connected with a network entity. Forexample, as described herein, the remote UE 466 and/or the communicationcomponent 420 may execute the scheduling component 426 to transmit, onat least one sidelink channel 430, a scheduling request to a relay UE464 connected with a network entity (e.g., base station 462).

At block 904, the method may receive, on one or more sidelink channels,a scheduling indication including a resource grant from the relay UE inresponse to transmitting the scheduling request. For example, asdescribed herein, the remote UE 466 and/or the communication component420 may execute the scheduling component 426 to receive, on one or moresidelink channels (e.g., sidelink cahnnel 430), a scheduling indicationincluding a resource grant from the relay UE 464 in response totransmitting the scheduling request.

In some aspects, the resource grant may correspond to an allocation ofresources by the relay UE 464 on a sidelink interface for communicationbetween the remote UE 466 and the relay UE 464. In some aspects, thescheduling request may be transmitted according to a code-divisionmultiplexing scheme. In some aspects, receiving the schedulingindication may include receiving SCI including an indication of anupcoming scheduling indication transmission, the indication beingdifferent from the scheduling indication and receiving the schedulingindication corresponding to a MAC CE within a data portion of a sidelinktransmission from the relay UE 464.

In some aspects, the scheduling request may be transmitted on a periodicresource. Further, for instance, the periodic resource may be allocatedwhen the remote UE links to the relay UE. In some aspects, the methodmay further transmit, on the at least one sidelink channel 430, SCIincluding a flag indicating an upcoming transmission of a buffer statusreport within a data portion of the upcoming transmission, and transmit,on the at least one sidelink channel 430, a buffer status report as aMAC CE within the data portion.

FIG. 10 is a flowchart 1000 of a method of scheduling resources at arelay UE. The method may be performed by a UE (e.g., UE 464). At block1002, the method may receive, on at least one sidelink channel, ascheduling request from a remote UE. For example, as described herein,the relay UE 464 and/or the relay component 410 may execute thescheduling determination component 416 to receive, on at least onesidelink channel 430, a scheduling request from a remote UE 466. Atblock 1004, the method may determine, by the relay UE, a resource grantfor the remote UE in response to receiving the scheduling request. Forexample, as described herein, the relay UE 464 and/or the relaycomponent 410 may execute the scheduling determination component 416 todetermine, by the relay UE 464, a resource grant for the remote UE 466in response to receiving the scheduling request. At block 1006, themethod may transmit, on one or more sidelink channels, a schedulingindication including the resource grant to the remote UE. For example,as described herein, the relay UE 464 and/or the relay component 410 mayexecute the scheduling determination component 416 to transmit, on oneor more sidelink channels (e.g., sidelink channel 430), a schedulingindication including the resource grant to the remote UE 466.

In some aspects, the scheduling request may be received on a periodicresource in accordance with a code-division multiplexing scheme. In someaspects, the method may further receive, on the sidelink channel 430,another scheduling request from a distinct remote UE on the periodicresource, identify at least one first code associated with the remote UE466 used in the code-division multiplexing scheme and at least onesecond code associated with the distinct remote UE used in thecode-division multiplexing scheme, the at least one first code beingdifferent from the at least one second code, determine a resource grantfor the distinct remote UE based on identifying the at least one secondcode associated with the distinct remote UE, and transmitting, to theremote UE 466 on the one or more sidelink channels (e.g., sidelinkchannel 430), another scheduling indication including the resource grantfor the remote UE 466.

In some aspects, transmitting the scheduling indication may includetransmitting, to the remote UE 466 on the one or more sidelink channels(e.g., sidelink channel 430), the scheduling indication including theresource grant to the remote UE 466 based on a determination of the atleast one first code associated with the remote UE 466. In some aspects,transmitting the scheduling indication may include transmitting SCIincluding an indication of an upcoming scheduling indicationtransmission to the remote UE 466, and transmitting the schedulingindication corresponding to a MAC CE within a data portion of a sidelinktransmission to the remote UE 466. In some aspects, the method mayfurther receive, from the remote UE 466 on the at least one sidelinkchannel 430, SCI including a flag indicating an upcoming transmission ofa buffer status report within a data portion of the upcomingtransmission, and receive, from the remote UE 466 on the at least onesidelink channel 430, a buffer status report as a MAC CE within the dataportion.

FIG. 11 is a conceptual data flow diagram 1100 illustrating the dataflow between different means/components in an exemplary apparatus 1102.The apparatus may be a relay UE. The apparatus includes a receptioncomponent 1104, a transmission component 1106, an RNTI component 412, aresource allocation component 414, and a scheduling determinationcomponent 416. The apparatus 1102 may receive communication from a basestation 1130 via the reception component 1104, and may transmitcommunication to the base station 1130 via the transmission component1106. Further, the apparatus 1102 may receive communication from aremote UE 1140 via the reception component 1104, and may transmitcommunication to the remote UE 1140 via the transmission component 1106.The RNTI component 412, the resource allocation component 414, and thescheduling determination component 416 may facilitate D2D communicationas described herein with respect to FIG. 4.

The apparatus may include additional components that perform each of theblocks of the algorithm in the aforementioned flowcharts of FIGS. 5, 7,and 10. As such, each block in the aforementioned flowcharts of FIGS. 5,7, and 10 may be performed by a component and the apparatus may includeone or more of those components. The components may be one or morehardware components specifically configured to carry out the statedprocesses/algorithm, implemented by a processor configured to performthe stated processes/algorithm, stored within a computer-readable mediumfor implementation by a processor, or some combination thereof.

FIG. 12 is a diagram 1200 illustrating an example of a hardwareimplementation for an apparatus 1202′ employing a processing system1214. The processing system 1214 may be implemented with a busarchitecture, represented generally by the bus 1224. The bus 1224 mayinclude any number of interconnecting buses and bridges depending on thespecific application of the processing system 1214 and the overalldesign constraints. The bus 1224 links together various circuitsincluding one or more processors and/or hardware components, representedby the processor 1204, the components 1104, 1106, 412, 414, 416, and thecomputer-readable medium/memory 1206. The bus 1224 may also link variousother circuits such as timing sources, peripherals, voltage regulators,and power management circuits, which are well known in the art, andtherefore, will not be described any further.

The processing system 1214 may be coupled to a transceiver 1210. Thetransceiver 1210 is coupled to one or more antennas 1220. Thetransceiver 1210 provides a means for communicating with various otherapparatus over a transmission medium. The transceiver 1210 receives asignal from the one or more antennas 1220, extracts information from thereceived signal, and provides the extracted information to theprocessing system 1214, specifically the reception component 1104 Inaddition, the transceiver 1210 receives information from the processingsystem 1214, specifically the transmission component 1106, and based onthe received information, generates a signal to be applied to the one ormore antennas 1220. The processing system 1214 includes a processor 1204coupled to a computer-readable medium/memory 1206. The processor 1204 isresponsible for general processing, including the execution of softwarestored on the computer-readable medium/memory 1206. The software, whenexecuted by the processor 1204, causes the processing system 1214 toperform the various functions described supra for any particularapparatus. The computer-readable medium/memory 1206 may also be used forstoring data that is manipulated by the processor 1204 when executingsoftware. The processing system 1214 further includes at least one ofthe components 1104, 1106, 412, 414, and 416. The components may besoftware components running in the processor 1204, resident/stored inthe computer readable medium/memory 1206, one or more hardwarecomponents coupled to the processor 1204, or some combination thereof.The processing system 1214 may be a component of the UE 350 and mayinclude the memory 360 and/or at least one of the TX processor 368, theRX processor 356, and the controller/processor 359.

In one configuration, the apparatus 1202/1202′ for wirelesscommunication includes means for receiving, on at least one sidelinkchannel, a scheduling request from a remote UE, means for determining,by the relay UE, a resource grant for the remote UE in response toreceiving the scheduling request, and means for transmitting, on one ormore sidelink channels, a scheduling indication including the resourcegrant to the remote UE.

The aforementioned means may be one or more of the aforementionedcomponents of the apparatus 1102 and/or the processing system 1214 ofthe apparatus 1202′ configured to perform the functions recited by theaforementioned means. As described supra, the processing system 1214 mayinclude the TX Processor 368, the RX Processor 356, and thecontroller/processor 359. As such, in one configuration, theaforementioned means may be the TX Processor 368, the RX Processor 356,and the controller/processor 359 configured to perform the functionsrecited by the aforementioned means.

FIG. 13 is a conceptual data flow diagram 1300 illustrating the dataflow between different means/components in an exemplary apparatus 1302.The apparatus may be a remote UE. The apparatus includes a receptioncomponent 1304, a transmission component 1306, an RNTI receptioncomponent 422, a resource component 424, and a scheduling component 426.The apparatus 1302 may receive communication from a base station 1330via the reception component 1304, and may transmit communication to thebase station 1330 via the transmission component 1306. Further, theapparatus 1302 may receive communication from a remote UE 1340 via thereception component 1304, and may transmit communication to the remoteUE 1340 via the transmission component 1306. The RNTI receptioncomponent 422, the resource component 424, and the scheduling component426 may facilitate D2D communication as described herein with respect toFIG. 4.

The apparatus may include additional components that perform each of theblocks of the algorithm in the aforementioned flowcharts of FIGS. 6, 8,and 9. As such, each block in the aforementioned flowcharts of FIGS. 6,8, and 9 may be performed by a component and the apparatus may includeone or more of those components. The components may be one or morehardware components specifically configured to carry out the statedprocesses/algorithm, implemented by a processor configured to performthe stated processes/algorithm, stored within a computer-readable mediumfor implementation by a processor, or some combination thereof.

FIG. 14 is a diagram 1400 illustrating an example of a hardwareimplementation for an apparatus 1402′ employing a processing system1414. The processing system 1414 may be implemented with a busarchitecture, represented generally by the bus 1424. The bus 1424 mayinclude any number of interconnecting buses and bridges depending on thespecific application of the processing system 1214 and the overalldesign constraints. The bus 1424 links together various circuitsincluding one or more processors and/or hardware components, representedby the processor 1204, the components 1304, 1306 422, 424, 426, and thecomputer-readable medium/memory 1406. The bus 1424 may also link variousother circuits such as timing sources, peripherals, voltage regulators,and power management circuits, which are well known in the art, andtherefore, will not be described any further.

The processing system 1414 may be coupled to a transceiver 1410. Thetransceiver 1410 is coupled to one or more antennas 1420. Thetransceiver 1410 provides a means for communicating with various otherapparatus over a transmission medium. The transceiver 1410 receives asignal from the one or more antennas 1420, extracts information from thereceived signal, and provides the extracted information to theprocessing system 1414, specifically the reception component 1304 Inaddition, the transceiver 1410 receives information from the processingsystem 1414, specifically the transmission component 1306, and based onthe received information, generates a signal to be applied to the one ormore antennas 1420. The processing system 1414 includes a processor 1404coupled to a computer-readable medium/memory 1406. The processor 1404 isresponsible for general processing, including the execution of softwarestored on the computer-readable medium/memory 1406. The software, whenexecuted by the processor 1404, causes the processing system 1414 toperform the various functions described supra for any particularapparatus. The computer-readable medium/memory 1406 may also be used forstoring data that is manipulated by the processor 1404 when executingsoftware. The processing system 1414 further includes at least one ofthe components 1304, 1306, 422, 424, and 426. The components may besoftware components running in the processor 1404, resident/stored inthe computer readable medium/memory 1406, one or more hardwarecomponents coupled to the processor 1204, or some combination thereof.The processing system 1414 may be a component of the UE 350 and mayinclude the memory 360 and/or at least one of the TX processor 368, theRX processor 356, and the controller/processor 359.

In one configuration, the apparatus 1402/1402′ for wirelesscommunication includes means for transmitting, on at least one sidelinkchannel, a scheduling request to a relay UE connected with a networkentity, and means for receiving, on one or more sidelink channels, ascheduling indication including a resource grant from the relay UE inresponse to transmitting the scheduling request.

The aforementioned means may be one or more of the aforementionedcomponents of the apparatus 1302 and/or the processing system 1414 ofthe apparatus 1402′ configured to perform the functions recited by theaforementioned means. As described supra, the processing system 1414 mayinclude the TX Processor 368, the RX Processor 356, and thecontroller/processor 359. As such, in one configuration, theaforementioned means may be the TX Processor 368, the RX Processor 356,and the controller/processor 359 configured to perform the functionsrecited by the aforementioned means.

It is understood that the specific order or hierarchy of blocks in theprocesses/flowcharts disclosed is an illustration of exemplaryapproaches. Based upon design preferences, it is understood that thespecific order or hierarchy of blocks in the processes/flowcharts may berearranged. Further, some blocks may be combined or omitted. Theaccompanying method claims present elements of the various blocks in asample order, and are not meant to be limited to the specific order orhierarchy presented.

The previous description is provided to enable any person skilled in theart to practice the various aspects described herein. Variousmodifications to these aspects will be readily apparent to those skilledin the art, and the generic principles defined herein may be applied toother aspects. Thus, the claims are not intended to be limited to theaspects shown herein, but is to be accorded the full scope consistentwith the language claims, wherein reference to an element in thesingular is not intended to mean “one and only one” unless specificallyso stated, but rather “one or more.” The word “exemplary” is used hereinto mean “serving as an example, instance, or illustration.” Any aspectdescribed herein as “exemplary” is not necessarily to be construed aspreferred or advantageous over other aspects. Unless specifically statedotherwise, the term “some” refers to one or more. Combinations such as“at least one of A, B, or C,” “one or more of A, B, or C,” “at least oneof A, B, and C,” “one or more of A, B, and C,” and “A, B, C, or anycombination thereof” include any combination of A, B, and/or C, and mayinclude multiples of A, multiples of B, or multiples of C. Specifically,combinations such as “at least one of A, B, or C,” “one or more of A, B,or C,” “at least one of A, B, and C,” “one or more of A, B, and C,” and“A, B, C, or any combination thereof” may be A only, B only, C only, Aand B, A and C, B and C, or A and B and C, where any such combinationsmay contain one or more member or members of A, B, or C. All structuraland functional equivalents to the elements of the various aspectsdescribed throughout this disclosure that are known or later come to beknown to those of ordinary skill in the art are expressly incorporatedherein by reference and are intended to be encompassed by the claims.Moreover, nothing disclosed herein is intended to be dedicated to thepublic regardless of whether such disclosure is explicitly recited inthe claims. The words “module,” “mechanism,” “element,” “device,” andthe like may not be a substitute for the word “means.” As such, no claimelement is to be construed as a means plus function unless the elementis expressly recited using the phrase “means for.”

What is claimed is:
 1. A method of wireless communication at a remoteuser equipment (UE), comprising: transmitting, on a first sidelinkchannel, a scheduling request to a relay UE connected with a networkentity; receiving, on a second sidelink channel, a scheduling indicationincluding a resource grant from the relay UE in response to transmittingthe scheduling request; transmitting, on at least one resource allocatedby the resource grant from the relay UE via the first sidelink channel,a sidelink control indication (SCI) indicating an upcoming transmissionof a buffer status report in a data portion of the upcomingtransmission, the buffer status report is associated with the firstsidelink channel; and transmitting, on the first sidelink channel, thebuffer status report as a medium access control (MAC) control element(CE) within the data portion.
 2. The method of claim 1, wherein theresource grant corresponds to an allocation of resources by the relay UEon a sidelink interface for communication between the remote UE and therelay UE.
 3. The method of claim 1, wherein the scheduling request istransmitted according to a code-division multiplexing scheme.
 4. Themethod of claim 1, wherein receiving the scheduling indication includes:receiving the SCI of transmission of the buffer status report, the SCIdifferent from the scheduling indication; and receiving the schedulingindication corresponding to a medium access control (MAC) controlelement (CE) within a data portion of a sidelink transmission from therelay UE.
 5. The method of claim 1, wherein the scheduling request istransmitted on a periodic resource.
 6. The method of claim 5, whereinthe periodic resource is allocated when the remote UE links to the relayUE.
 7. A method of wireless communication at a relay user equipment(UE), comprising: receiving, on a first sidelink channel, a schedulingrequest from a remote UE; determining, by the relay UE, a resource grantfor the remote UE in response to receiving the scheduling request;transmitting, on a second sidelink channel, a scheduling indicationincluding the resource grant to the remote UE; receiving, from theremote UE on at least one resource allocated by the resource grant fromthe relay UE via the first sidelink channel, a sidelink controlinformation (SCI) indicating an upcoming transmission of a buffer statusreport in a data portion of the upcoming transmission, the buffer statusreport is associated with the first sidelink channel; and receiving,from the remote UE on the first sidelink channel, a buffer status reportas a MAC CE within the data portion.
 8. The method of claim 7, whereinthe scheduling request is received on a periodic resource in accordancewith a code-division multiplexing scheme, the method further comprising:receiving, on the first sidelink channel, another scheduling requestfrom a distinct remote UE on the periodic resource; identifying at leastone first code associated with the remote UE used in the code-divisionmultiplexing scheme and at least one second code associated with thedistinct remote UE used in the code-division multiplexing scheme, the atleast one first code being different from the at least one second code;determining a resource grant for the distinct remote UE based onidentifying the at least one second code associated with the distinctremote UE; and transmitting, to the remote UE on the second sidelinkchannel, another scheduling indication including the resource grant forthe remote UE.
 9. The method of claim 8, wherein transmitting thescheduling indication includes transmitting, to the remote UE on thesecond sidelink channel, the scheduling indication including theresource grant to the remote UE based on a determination of the at leastone first code associated with the remote UE.
 10. The method of claim 7,wherein transmitting the scheduling indication includes: transmittingthe SCI of transmission of the buffer status report to the remote UE;and transmitting the scheduling indication corresponding to a mediumaccess control (MAC) control element (CE) within a data portion of asidelink transmission to the remote UE.
 11. A remote user equipment (UE)for wireless communication, comprising: a memory; and a processor incommunication with the memory, wherein the processor is configured to:transmit, on at least one sidelink channel, a scheduling request to arelay UE connected with a network entity; receive, on one or moresidelink channels, a scheduling indication including a resource grantfrom the relay UE in response to transmitting the scheduling request;transmit, on at least one resource allocated by the resource grant fromthe relay UE via the first sidelink channel, a sidelink controlindication (SCI) indicating an upcoming transmission of a buffer statusreport in a data portion of the upcoming transmission, the buffer statusreport is associated with the first sidelink channel; and transmit, onthe at least one sidelink channel, the buffer status report as a mediumaccess control (MAC) control element (CE) within the data portion. 12.The remote UE of claim 11, wherein the resource grant corresponds to anallocation of resources by the relay UE on a sidelink interface forcommunication between the remote UE and the relay UE.
 13. The remote UEof claim 11, wherein the scheduling request is transmitted according toa code-division multiplexing scheme.
 14. The remote UE of claim 11,wherein to receive the scheduling indication, the processor is furtherconfigured to: receive the SCI of the transmission of the buffer statusreport, the SCI different from the scheduling indication; and receivethe scheduling indication corresponding to a medium access control (MAC)control element (CE) within a data portion of a sidelink transmissionfrom the relay UE.
 15. The remote UE of claim 11, wherein the schedulingrequest is transmitted on a periodic resource.
 16. The remote UE ofclaim 15, wherein the periodic resource is allocated when the remote UElinks to the relay UE.
 17. A relay user equipment (UE) for wirelesscommunication, comprising: a memory; and a processor in communicationwith the memory, wherein the processor is configured to: receive, on afirst sidelink channel, a scheduling request from a remote UE; determinea resource grant for the remote UE in response to receiving thescheduling request; transmit, on a second sidelink channel, a schedulingindication including the resource grant to the remote UE; receive, fromthe remote UE on at least one resource allocated by the resource grantfrom the relay UE via the first sidelink channel, a sidelink controlindication (SCI) indicating an upcoming transmission of a buffer statusreport in a data portion of the upcoming transmission, the buffer statusreport is associated with the first sidelink channel; and receive, fromthe remote UE on the first sidelink channel, a buffer status report as aMAC CE within the data portion.
 18. The relay UE of claim 17, whereinthe scheduling request is received on a periodic resource in accordancewith a code-division multiplexing scheme, the processor furtherconfigured to: receive, on the first sidelink channel, anotherscheduling request from a distinct remote UE on the periodic resource;identify at least one first code associated with the remote UE used inthe code-division multiplexing scheme and at least one second codeassociated with the distinct remote UE used in the code-divisionmultiplexing scheme, the at least one first code being different fromthe at least one second code; determine a resource grant for thedistinct remote UE based on identifying the at least one second codeassociated with the distinct remote UE; and transmit, to the remote UEon the one or more sidelink channels, another scheduling indicationincluding the resource grant for the remote UE.
 19. The relay UE ofclaim 18, wherein to transmit the scheduling indication, the processoris further configured to transmit, to the remote UE on the secondsidelink channel, the scheduling indication including the resource grantto the remote UE based on a determination of the at least one first codeassociated with the remote UE.
 20. The relay UE of claim 17, wherein totransmit the scheduling indication, the processor is further configuredto: transmit the SCI of the transmission of the buffer status report tothe remote UE; and transmit the scheduling indication corresponding to amedium access control (MAC) control element (CE) within a data portionof a sidelink transmission to the remote UE.
 21. A remote user equipment(UE) for wireless communication, comprising: means for transmitting, ona first sidelink channel, a scheduling request to a relay UE connectedwith a network entity; means for receiving, on a second sidelinkchannel, a scheduling indication including a resource grant from therelay UE in response to transmitting the scheduling request; means fortransmitting, on at least one resource allocated by the resource grantfrom the relay UE via the first sidelink channel, a sidelink controlindication (SCI) indicating an upcoming transmission of a buffer statusreport in a data portion of the upcoming transmission, the buffer statusreport is associated with the first sidelink channel; and means fortransmitting, on the first sidelink channel, the buffer status report asa medium access control (MAC) control element (CE) within the dataportion.
 22. A relay user equipment (UE) for wireless communication,comprising: means for receiving, on a first sidelink channel, ascheduling request from a remote UE; means for determining a resourcegrant for the remote UE in response to receiving the scheduling request;means for transmitting, on a second sidelink channel, a schedulingindication including the resource grant to the remote UE; means forreceiving, from the remote UE on at least one resource allocated by theresource grant from the relay UE via the first sidelink channel, asidelink control indication (SCI) indicating an upcoming transmission ofa buffer status report in a data portion of the upcoming transmission,the buffer status report is associated with the first sidelink channel;and means for receiving, from the remote UE on the first sidelinkchannel, a buffer status report as a MAC CE within the data portion. 23.A non-transitory computer-readable medium storing computer executablecode for wireless communications at a remote user equipment (UE),comprising code for: transmitting, on a first sidelink channel, ascheduling request to a relay UE connected with a network entity;receiving, on a second sidelink channel, a scheduling indicationincluding a resource grant from the relay UE in response to transmittingthe scheduling request; transmitting, on at least one resource allocatedby the resource grant from the relay UE via the first sidelink channel,a sidelink control indication (SCI) indicating an upcoming transmissionof a buffer status report in a data portion of the upcomingtransmission, the buffer status report is associated with the firstsidelink channel; and transmitting, on the first sidelink channel, thebuffer status report as a medium access control (MAC) control element(CE) within the data portion.
 24. A non-transitory computer-readablemedium storing computer executable code for wireless communications at arelay user equipment (UE), comprising code for: receiving, on a firstsidelink channel, a scheduling request from a remote UE; determining, bythe relay UE, a resource grant for the remote UE in response toreceiving the scheduling request; transmitting, on a second sidelinkchannel, a scheduling indication including the resource grant to theremote UE; receiving, from the remote UE on at least one resourceallocated by the resource grant from the relay UE via the first sidelinkchannel, a sidelink control indication (SCI) indicating an upcomingtransmission of a buffer status report in a data portion of the upcomingtransmission, the buffer status report is associated with the firstsidelink channel; and receiving, from the remote UE on the firstsidelink channel, a buffer status report as a MAC CE within the dataportion.